He Doesn't Know
by GreyEyesGlaringAtShonda
Summary: [MarkAddison post Yesterday oneshot] Derek doesn't know that they were in love. Derek doesn't know they moved in together. And he CERTAINLY doesn't know Addison's biggest secret of all.


**He Doesn't Know**

By GreyEyedGirl Derek doesn't know they loved each other. Addison's thoughts/feelings during "Yesterday."

Author's note: Just a one-shot for Addison's thoughts and feelings during "Yesterday." Obviously, I hate the scary redhead who broke Derek and Meredith up, but I couldn't help really respecting Kate Walsh as an actress during this ep. Read&Review. Feedback is my crack. Support my habit?

_CRASH._

That one noise, one word, an onomatopoeia known by all, described so many things in that moment.

_CRASH _went Addison's mind, seeing Mark standing there with Meredith.

_CRASH_ went Addison's heart, catching a glimpse of the handsome, rugged face she'd fallen in love with.

**CRASH** went Addison's world, as Derek's fist went, crashing, into the side of Mark's face.

_No._

And now Richard knew, too.

Did that mean everyone knew? Everyone knew what she was, a cheater, a tramp, one who associated herself with Dirty Mistresses?

Derek didn't know.

Well. Of course Derek _knew,_ he'd seen them together. But there was still so, so much he didn't know. Things he could never know, because she could never tell him.

Addison Forbes Montgomery Shepherd (ADDISON FORBES MONTGOMERY SHEPHERD!) had fallen in love with someone other than her husband. Worse, it had been her husband's best friend. _Her_ best friend.

She didn't know when it all started. Oh, sure, she knew when the first time was that they had been together, but she didn't know when the love started. Just that it had come fast, hurtling, crashing and wrapping itself around her. Maybe it was his eyes, his smile, his dry comments that made her laugh so. Mark was someone who made her happy, who made her laugh. His smile brought a twinkle to her blue eyes that usually didn't exist in the cold bright orbs.

Strangely enough, though, the night they had first been together hadn't been caused by their laughter. Addison's eyes filled with fiery tears as she tried not to let herself remember. She couldn't _not_ remember.

Addison had known what was happening. Though the stirring inside her was so strong it was to be unfamiliar, she couldn't deny the feelings there. She was in love with Mark Sloan.

She knew this was happening, but she couldn't force herself to stay away from him, try as she might to suffocate her urges.

She had been trying to stay away from him, but one night when Derek was tied up at the hospital with surgeries, Mark had come for her. She remembered the look in his blazing eyes as he confessed what he was feeling, and she had tried to back away, forcing Derek's face to come into her mind.

Mark had told her he loved her. Her heart had stopped beating, the sounds of his voice twirling in the air, as a soft mist clouded over her brain. The taste of his lips...they'd been soft, a little scratchy from his peach fuzz, but they had caused Addison to spill over, breaking like a jar that had been smashed to the floor.

Derek had been gone, he was always gone, and as the weeks passed (those _fabulous_ weeks) Addison had felt herself crashing more and more into the fiery pit that was Forbidden Love

**Derek didn't know.** He could never what had happened, how far into each other Mark and Addison had fell after Derek had left for Seattle. While Derek was chasing Meredith, smelling her hair and sharing with her the ferry boats, Mark had been swooning over Addison, and Addison had felt herself feeling something she'd never felt before. She'd lived with him in his penthouse, and she'd never forget the feeling of wonder she'd get each morning waking up and being able to look into Those eyes. So soft and blue and beautiful.

"You're marriage is over, Addison."

It was these words that Addison heard night after night in her head, and when Mark said them it was only a reflection of her own thoughts. She could feel her eyes brimming, and she carefully avoided the deep gaze of the man standing in front of her.

He was so close to her. So, so close. Her heart still beat slower when she was in his presence, and the way he was standing there, the way he was looking at her, was enough to send Addison's thoughts into a tailspin.

"I'm going to the bar across the street. Meet me there."

Addison's mind froze, and she felt her breathing slow, the tears behind her eyes screaming, pleading at her to let them out. Her insides were cold.

He was standing too close, she couldn't let this happen again. She couldn't let herself go back to him, letting herself relax in those big strong arms. She just _couldn't._

And now. Her heart was hurting, thinking of all Mark's words, old and new. She could hear Derek's slow, grizzly breathing, in that deep state between wake and sleep as he stared blankly at the TV screen. She knew who he was thinking about.

Memories flashed through her head, and all the things that had happened in the past year kept swinging forward. Falling in love with the last person she should have. Losing Derek. Losing the baby she and Mark had created.

She sat very still, remembering the feeling that she'd had when she looked down at the pregnancy test, with the little positive symbol in check. She'd been scared, knowing what was going to happen, but the sight of Mark's face soothed her.

The night she'd lost the baby had been the end of more than one life, more than one love. It was a wake-up call, reminding her of what she'd done, and who all she had hurt. Her mind spinning, she had boarded a plane a week later, fully intending to win her husband back. And since then, things had gotten even crazier, more painful on the already shattered Addison Montgomery. _Mark_ was here.

Derek could never, ever know.


End file.
